1. Field
Embodiments relate to a semiconductor device, and more particularly, to a semiconductor device including a plurality of sensor pads and a plurality of normal pads for an electric die sort (EDS) test.
2. Description of the Related Art
An overall process of manufacturing a semiconductor device can include (1) a wafer manufacturing process, (2) a wafer EDS test process, and (3) a wafer packaging process. The EDS test process is a pre-process of the wafer packaging process, as described above, and during the EDS test the electrical characteristics of semiconductor chips on the wafer may be tested in a wafer state. For example, the EDS test may check whether data output after an electrical signal is applied to pads of a semiconductor device is normal. In particular, the electrical signal may be applied to the pads of the semiconductor device via needles, and data is output from the semiconductor device in response to the applied electrical signal.
To efficiently perform the EDS test on the wafer, each needle providing the electrical signal is preferably accurately aligned to a corresponding pad of the semiconductor device. As the capacity of semiconductor devices increases, however, the number of pads required for inputting/outputting an electrical signal remarkably increases. As such, it may be difficult for each needle to contact an accurate position on the corresponding pad of the semiconductor device. Moreover, when a needle fails to contact an accurate position on the corresponding pad, e.g., the needle may contact an edge portion of the pad, a serious quality defect may be generated. To address this issue, and to assist the needle in contacting an accurate position, a sensor pad may be used on the semiconductor device.
A single sensor pad, however, has limits in functionality. For example, even when a defect is detected in contacting a normal pad, the position of an applied electric signal on the sensor pad may inhibit the EDS test from detecting the defect.
The single sensor pad also has limits in checking the arrangement of needles when the semiconductor device includes pads arranged in various directions. For example, when the pads are arranged in a horizontal direction and a vertical direction, the needles may also be arranged in both the horizontal direction and the vertical direction. The single sensor pad, however, may only be able to check the arrangement of needles in one direction.
In the packaging process performed after the EDS test process, a probing mark generated on the pads due to the EDS test may be problematic. In particular, the probing mark signifies a mark generated as the needle contacts the corresponding pad during the EDS test. The probing mark, however, may affect the reliability of the semiconductor device, e.g., the probing mark may affect the reliability of a writing process in the packaging process.